Numerous patents for heating devices for enabling the starting of internal combustion engines in cold weather attest to the need for engine warming in very cold weather. While modern engines and oils are generally very good at starting when moderately cold, even the very best of engines are unlikely to start if they are -25.degree. F. or colder. Combinations of oil viscosity, battery or starter condition, engine size, low speed torque characteristics, etc. may make even much more normal temperatures, such as '15.degree. F., too cold to start some engines without some warming means being applied. The point is that engine warmers frequently are needed even in relatively temperate geographical areas, i.e., not just in the extreme cold weather areas. The concept is a viable one based on the quantity of engine warmers which have been proposed and/or produced.
Several related patents are discussed below:
a. ENGINE HEATERS
As stated above, numerous patents exist for engine heaters using various means of accomplishing the warming of an engine. U.S. Pat. Nos. 1,786,130 to W. Schoenfeld, 3,114,360 to C.D. Snelling, 3,809,527 to R. Newman, and 4,445,469 to L. Suhayda describe means of warming the underside and/or oil pan of automobile engines for the purpose of starting said engines in a cold environment.
It can be seen that the invention herein described is intended to accomplish the same general result but is much simpler and cheaper as well as being substantially different in configuration from the other patented engine heaters noted above. These four existing patents are not suitable for usage either away from home or away from power sources. None of the four patents cited describe a simple, low cost, compact emergency type of heater which is to be carried in the vehicle's trunk or equivalent stowage space in case it is needed.
The many patented engine heaters which utilize electric heating elements to heat engines by heating the block directly, or the engine coolant fluid, or the engine lubricating oil as in U.S. Pat. No. 3,171,015 Dip Stick Heater to G.H. Grinde are obviously quite different from the invention described herein.
U.S. Pat. Nos. 1,414,539 granted to Wilson, 3,213,263 to Steenbergen, and 4,370,956 to Moser are representative of many other engine heater patents which have been granted all of which differ substantially from this invention.
An examination of the other patented engine heaters will show that they fall into one or more of the following categories of differences from this invention.
The other patents are different in that:
(a) They either require an external electric energy source, or
(b) They require some, usually permanent, installation work on the vehicle, or
(c) They are expensive and/or complex systems, or
(d) They are bulky and not intended to be carried in the vehicle, or
(e) They are not inexpensive, compact devices intended to be carried in the vehicle for emergency usage in remote areas without either installation or external power sources required.
b. FLAME SHIELDS:
A portion of the invention includes means for shielding the heater flame from wind, minimizing heat loss and also preventing direct flame impingement on the bottom of the engine oil pan. Various flame protecting means are presently patented. U.S. Pat. No. 1,566,758 to Martin describes a protecting hood for gasoline blowtorches and the like. U.S. Pat. No. 3,276,509 to Fredhold and Wilkinson describes a flame protector for gas burners of the type used in gas refrigerators used for house trailers, campers and the like. U.S. Pat. No. 3,630,649 to Hancock and Westerman describes several means of shrouding and controlling gas burner flames.
The direct impingement barrier and flame protection means employed in this invention, while having some commonality with the cited prior art and other flame protectors, will however be found upon careful examination to be unique in their totality to suit the objective of the invention.
The flame protection means employed in the preferred embodiments of this invention is unlike the shrouded burners of Hancock and Westerman, U.S. Pat. No. 3,630,649 in the following ways:
1. There is no attempt made to alter the flame shape from that of the standard torch burner to which the invention is attached. The standard burner has its own flame holding features.
2. In this invention, the intake air approaching the inlet to the standard torch burner passes through an annular space created by an intake shielding hollow cylinder which is closed off at its lower end and which, at its upper end, has an inside diameter larger than the standard torch burner or nozzle outside diameter and which surrounds the lower portion of the standard torch burner or nozzle. This shielding cylinder causes the intake air to make two changes in direction and prevents wind pressure from acting directly on the burner air intake and makes the air intake pressure nearly equal to the exhaust discharge pressure when working in combination with the upper flame shield of the invention.
3. At the top of the flame protecting enclosure or shield there is a hinged flame impingement barrier which has an easy locking and unlocking feature.
4. None of the Hancock and Westerman burners have the mixing of air and gas in the axially drafted air intake manner common to commercial propane torch burners which this invention utilizes.
The flame protection means utilized in the preferred embodiments of this invention is also unlike the flame protection means which are described in U.S. Pat. Nos. 1,566,758 to Martin and 3,276,509 to Fredhold and Wilkinson in the following ways:
1. An intake shielding hollow cylinder is configured and fitted to the standard torch nozzle and its gas supply pipe in such a way that, in combination with the upper shielding cone or the like, wind pressure is essentially balanced between inlet and outlet sides of the torch burner or nozzle. Without this approximate balancing of wind pressure, strong winds will either seriously disrupt the normal inlet air draft induction into the burner mixing chamber of common propane torches or also, in some cases, back up the exhaust gas discharge and cause extinguishment of the flame by either means.
2. The flame protection means also includes a quick acting lock/unlock feature which allows the top portion, which is primarily a flame impingement barrier but also part of the wind protection means for the flame, to be swung up and out of the way for lighting the torch then quickly locked down in its operating position.
3. The flame protection means in both of the preferred embodiments is configured so that the upper flame protector cone or the like slips over the upper end of a standard torch nozzle or burner and is simply clamped to it. The lower, intake, shielding hollow cylinder is also easily installed and its upper end forms an annular intake air flow passage between it and the lower part of the torch nozzle or burner.
The lower end of the lower, intake, shielding cylinder is sealed to the gas supply pipe preferably with a split high temperature resistant elastomer grommet or by some other means.
Note that in any event the preferred embodiments of the flame shielding means are only a portion of the invention and not the total invention which is primarily a novel and practical engine heater which quickly adapts standard propane torches for this purpose.